fa *mkdfa(const char *s, int anchor) /* does the real work of making a dfa */
/* anchor = 1 for anchored matches, else 0 */
{
Node *p, *p1;
fa *f;
p = reparse(s);
p1 = op2(CAT, op2(STAR, op2(ALL, NIL, NIL), NIL), p);
/* put ALL STAR in front of reg. exp. */
p1 = op2(CAT, p1, op2(FINAL, NIL, NIL));
/* put FINAL after reg. exp. */
poscnt = 0;
penter(p1); /* enter parent pointers and leaf indices */
if ((f = (fa *) calloc(1, sizeof(fa) + poscnt*sizeof(rrow))) == NULL)
overflo("out of space for fa");
f->accept = poscnt-1; /* penter has computed number of positions in re */
cfoll(f, p1); /* set up follow sets */
freetr(p1);
if ((f->posns[0] = (int *) calloc(1, *(f->re[0].lfollow)*sizeof(int))) == NULL)
overflo("out of space in makedfa");
if ((f->posns[1] = (int *) calloc(1, sizeof(int))) == NULL)
overflo("out of space in makedfa");
*f->posns[1] = 0;
f->initstat = makeinit(f, anchor);
f->anchor = anchor;
f->restr = (uschar *) tostring(s);
return f;
}
void penter(Node *p) /* set up parent pointers and leaf indices */
{
switch (type(p)) {
LEAF
info(p) = poscnt;
poscnt++;
break;
UNARY
penter(left(p));
parent(left(p)) = p;
break;
case CAT:
case OR:
penter(left(p));
penter(right(p));
parent(left(p)) = p;
parent(right(p)) = p;
break;
default: /* can't happen */
ERROR "can't happen: unknown type %d in penter", type(p) FATAL;
break;
}
}